Electric fracturing operation system

ABSTRACT

An electric fracturing operation system includes a water storage device, a fracturing device, a blending device and a sand mixing device, wherein the water storage device is a flexible water tank; the flexible water tank is connected with the blending device; the fracturing device includes multiple electrically-driven fracturing pumps; the blending device is configured to blend fracturing base fluid and storing the fracturing base fluid in a fluid preparing tank; an inlet of the sand mixing device is connected with the fluid preparing tank and a sand storage and conveying tank; an outlet of the sand mixing device is connected with inlets of all the electrically-driven fracturing pumps through low-pressure manifolds; and outlets of all the electrically-driven fracturing pumps are connected with a wellhead through high-pressure manifolds.

CROSS REFERENCE OF RELATED APPLICATION

The present invention claims priority under 35 U.S.C. 119(a-d) to CN 202010338831.5, filed Apr. 26, 2020 and titled as “An electric fracturing operation system” whose entire contents are incorporated by reference in the present invention.

BACKGROUND OF THE PRESENT INVENTION Field of Invention

The present invention relates to the field of oil gas field fracturing technology, and more particularly to an electric fracturing operation system.

Description of Related Arts

Hydraulic fracturing is a major stimulation measure in oil gas field exploration and development. It mainly uses the fracturing pump to inject the fracturing fluid into the wellbore under high pressure to create cracks in the formation, so as to improve the flow environment of oil in the underground, thus increasing the oil well productivity. After the fracturing operation is completed, the fracturing base fluid flows back to the ground, and the fracturing proppant remains in the cracks in the formation to prevent the cracks from closing, so that a large amount of oil and gas enters the wellbore through the cracks to be exploited.

At present, the fracturing operation system mainly includes multiple fracturing trucks, the fracturing blender truck, the measuring truck, the manifold fittings and the auxiliary device. During the operation, through the fracturing blender truck, slick water, proppant and various additives are mixed into the fracturing fluid, and then the fracturing fluid is supplied to the fracturing trucks through the connection manifold, is pressurized by the fracturing trucks and is injected into the bottom hole through the high-pressure manifold. The measuring truck monitors, analyzes and records the whole operation.

The existing fracturing operation has some shortcomings as follows. (1) The fracturing unit is large in volume and weight. The diesel engine drives the gearbox to actuate the fracturing pump through the transmission shaft, which is large in volume and weight, limited in transportation, and small in power density. (2) The existing fracturing operation is not environmental-friendly. During the operation, the fracturing devices (such as fracturing trucks and fracturing blender trucks) driven by the diesel engine will produce engine exhaust pollution and noise pollution, and the noise is more than 105 dBA, which seriously affects the normal life of the surrounding residents. (3) The existing fracturing operation is uneconomic. The fracturing devices driven by the diesel engine is relatively high in initial procurement cost, is high in consumed cost per unit output power during the operation, and is also high in daily maintenance cost of engine and gearbox. (4) The existing fracturing operation occupy a large area. The fracturing trucks driven by the diesel engine are small in power and large in number, resulting in the large floor area. (5) There are too many manifolds, so the existing fracturing operation has high security risk. The fracturing trucks driven by the diesel engine are small in power and large in number, so the number of connected high-pressure manifolds is large and the connection routes are complex. Moreover, the high-pressure manifolds obviously vibrate and are easy to be damaged, and even burst, which threatens the safety of devices and personnel. (6) It is inconvenient to store water for fracturing. A large amount of clean water is needed in hydraulic fracturing. The conventional method is to dig reservoirs or use a large number of water tanks with fixed capacity. However, the cycle of digging reservoirs is long, the cost thereof is high, the ground is not easy to recover; and the number of water tanks with fixed capacity is large and the floor area is large.

SUMMARY OF THE PRESENT INVENTION

An object of the present invention is to overcome deficiencies of current hydraulic fracturing operations to provide an electric fracturing operation system, which is able to reduce the volume and weight of existing fracturing units, and is economical and environmentally friendly. Moreover, the system is able to significantly reduce the cost of fracturing construction, the number of fracturing pumps and high-pressure manifolds with high-pressure level, and the floor area.

In order to achieve the object, the present invention adopts technical solutions as follows.

An electric fracturing operation system comprises a fracturing device, a water storage device, a blending device, a sand mixing device, a fluid preparing tank and a sand storage and conveying tank, wherein the fracturing device comprises multiple electrically-driven fracturing pumps and fracturing frequency conversion stations, the water storage device is connected with the blending device, the blending device is configured to blend fracturing base fluid and store the fracturing base fluid in the fluid preparing tank; the fluid preparing tank is connected with an inlet of the sand mixing device or inlets of the fracturing device, the sand storage and conveying tank is connected with the inlet of the sand mixing device, an outlet of the sand mixing device is connected with the inlets of the fracturing device through low-pressure manifolds, and a wellhead is connected with outlets of the fracturing device through high-pressure manifolds.

The present invention realizes fracturing by the electrically-driven fracturing pumps. The fracturing frequency conversion stations are configured to control a rotational speed of the electrically-driven fracturing pumps respectively; the water storage device is configured to storage clean water in fracturing operations; the blending device is configured to use the clean water from the water storage device to blend the fracturing base fluid and store the fracturing base fluid in the fluid preparing tank; both the fracturing base fluid in the fluid preparing tank and fracturing sand in the sand storage and conveying tank are transported to the sand mixing device; the sand mixing device distributes prepared fracturing fluid to each of the electrically-driven fracturing pumps through the low-pressure pipelines, and then after low-pressure fracturing fluid is pressurized into high-pressure fracturing fluid through the electrically-driven fracturing pumps, the high-pressure fracturing fluid is pressed into foundation through the high-pressure manifolds and the wellhead, so that the formation produces cracks for connecting natural fractures of the foundation, thereby improving the oil and gas passages, and increasing the oil and gas production. Moreover, when the fluid preparing tank is connected with inlets of the electrically-driven fracturing pumps, the prepared fracturing fluid is directly pushed into the foundation, so that the operation process without fracturing sand is realized. Compared with the diesel-driven fracturing pump, the electrically-driven fracturing pump is small in volume, is low in noise and cost, and has no exhaust emission pollution. In addition, by increasing the power of the electrically-driven fracturing pumps, the number of the electrically-driven fracturing pumps required is reduced, and simultaneously the number of the high-pressure manifolds with high-pressure level is decreased, so that the floor area is saved.

Preferably, a power source of the electric fracturing operation system is a public power grid or a power generation device. The use of two power sources is beneficial to improve the adaptability of the electric fracturing operation system to the operating environment.

Preferably, the water storage device is a flexible water tank. The clean water in the fracturing operation is stored by the flexible water tank. The flexible water tank has several times the capacity of the conventional water tank while occupying less space than the conventional water tank. Moreover, the flexible water tank is able to greatly reduce the transportation cost by folding transportation.

Preferably, electric energy provided by the public power grid or the power generation device enters a high-voltage distribution station, the high-voltage distribution station distributes the electric energy into at least one of the fracturing device, the water storage device, the blending device, the sand mixing device, the fluid preparing tank, the sand storage and conveying tank, the low-pressure manifolds and the high-pressure manifolds. The electric energy is distributed to every electric device by the high-voltage distribution station.

Preferably, the electric fracturing operation system further comprises a command and control center, which is powered by the high-voltage distribution station and is configured to control the fracturing device, the water storage device, the blending device, the sand mixing device, the fluid preparing tank, the sand storage and conveying tank, the low-pressure manifolds and the high-pressure manifolds. Therefore, the command and control center is used to control the coordination of various devices.

Preferably, any one of the fracturing device, the water storage device, the blending device, the sand mixing device, the fluid preparing tank, the sand storage and conveying tank, the low-pressure manifolds and the high-pressure manifolds is electrically driven for achieving full electric drive and no hydraulic drive.

Preferably, the fracturing device and the blending device are vehicle-mounted or skid-mounted, which is able to adapt to different operating environments.

Preferably, each of the fracturing frequency conversion stations is corresponding to one or two electrically-driven fracturing pumps. In practice, each of the fracturing frequency conversion stations is able to control one or two electrically-driven fracturing pumps, which is conductive to reducing a floor area of the fracturing frequency conversion stations.

Preferably, each of the electrically-driven fracturing pumps is a three-cylinder or five-cylinder plunger pump.

Preferably, the power generation device is a gas generator set, a diesel generator set or a turbine generator set.

Preferably, there are multiple water storage devices which are connected with each other in series and then connected with the blending device. According to the water quantity, the number of water storage devices is able to be increased or decreased to jointly realize the storage of fracturing water, which is more flexible and convenient to use.

Preferably, there are multiple fluid preparing tanks which are connected with each other in series and then connected with the sand mixing device. The number of fluid preparing tanks is able to be increased or decreased according to the amount of the fracturing base fluid after mixing, which is more flexible and convenient to use.

Preferably, the electric fracturing operation system further comprises an acid storage tank and an acid supply device, wherein the acid storage tank provides acid for the fracturing device through the acid supply device, and the acid supply device is powered by the high-voltage distribution station and controlled by the command and control center.

In summary, the present invention has some beneficial effects as follows.

(1) The present invention realizes fracturing by the electrically-driven fracturing pumps. The fracturing frequency conversion stations are configured to control a rotational speed of the electrically-driven fracturing pumps respectively; the water storage device is configured to storage clean water in fracturing operations; the blending device is configured to use the clean water from the water storage device to blend the fracturing base fluid and store the fracturing base fluid in the fluid preparing tank; both the fracturing base fluid in the fluid preparing tank and fracturing sand in the sand storage and conveying tank are transported to the sand mixing device; the sand mixing device distributes prepared fracturing fluid to each of the electrically-driven fracturing pumps through the low-pressure pipelines, and then after low-pressure fracturing fluid is pressurized into high-pressure fracturing fluid through the electrically-driven fracturing pumps, the high-pressure fracturing fluid is pressed into foundation through the high-pressure manifolds and the wellhead, so that the formation produces cracks for connecting natural fractures of the foundation, thereby improving the oil and gas passages, and increasing the oil and gas production. Moreover, when the fluid preparing tank is connected with the inlets of the electrically-driven fracturing pumps, the prepared fracturing fluid is directly pushed into the foundation, so that the operation process without fracturing sand is realized.

(2) Compared with the diesel-driven fracturing pump, the electrically-driven fracturing pump is small in volume, is low in noise and cost, and has no exhaust emission pollution. In addition, by increasing the power of the electrically-driven fracturing pumps, the number of the electrically-driven fracturing pumps required is reduced, and simultaneously the number of the high-pressure manifolds with high-pressure level is decreased, so that the floor area is saved.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of an electric fracturing operation system according to a preferred embodiment of the present invention.

FIG. 2 is a schematic diagram of the electric fracturing operation system according to another preferred embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention will be explained in detail with accompanying drawings as follows.

In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail with reference to the accompanying drawings and embodiments as below. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

First Embodiment

As shown in FIG. 1 , an electric fracturing operation system according to a first preferred embodiment of the present invention is illustrated, which comprises a fracturing device, a water storage device, a blending device, a sand mixing device, a fluid preparing tank and a sand storage and conveying tank, wherein the fracturing device comprises multiple electrically-driven fracturing pumps and fracturing frequency conversion stations, the water storage device is connected with the blending device, the blending device is configured to blend fracturing base fluid and store the fracturing base fluid in the fluid preparing tank, the fluid preparing tank is connected with an inlet of the sand mixing device or inlets of the fracturing device, the sand storage and conveying tank is connected with the inlet of the sand mixing device, an outlet of the sand mixing device is connected with the inlets of the fracturing device through low-pressure manifolds, and a wellhead is connected with outlets of the fracturing device through high-pressure manifolds.

The present invention realizes fracturing by the electrically-driven fracturing pumps. The fracturing frequency conversion stations are configured to control a rotational speed of the electrically-driven fracturing pumps respectively; the water storage device is configured to storage clean water in fracturing operations; the blending device is configured to use the clean water from the water storage device to prepare the fracturing base fluid and store the fracturing base fluid in the fluid preparing tank; both the fracturing base fluid in the fluid preparing tank and fracturing sand in the sand storage and conveying tank are transported to the sand mixing device; the sand mixing device distributes prepared fracturing fluid to each of the electrically-driven fracturing pumps through a low-pressure pipeline, and then after low-pressure fracturing fluid is pressurized into high-pressure fracturing fluid through the electrically-driven fracturing pumps, the high-pressure fracturing fluid is pressed into foundation through the high-pressure manifolds and the wellhead, so that the formation produces cracks for connecting natural fractures of the foundation, thereby improving the oil and gas passages, and increasing the oil and gas production. Moreover, when the fluid preparing tank is connected with the inlets of the electrically-driven fracturing pumps, the prepared fracturing base fluid is directly pushed into the foundation, so that the operation process without fracturing sand is realized. Compared with the diesel-driven fracturing pump, the electrically-driven fracturing pump is small in volume, is low in noise and cost, and has no exhaust emission pollution. In addition, by increasing the power of the electrically-driven fracturing pumps, the number of the electrically-driven fracturing pumps required is reduced, and simultaneously the number of high-pressure manifolds with high-pressure level is decreased, so that the floor area is saved.

According to the first preferred embodiment of the present invention, the power source of the electric fracturing operation system is a public power grid or a power generation device. The use of two power sources is beneficial to improve the adaptability of the electric fracturing operation system to the operating environment. Specifically, in some places with perfect power facilities, the public power grid is able to be directly used for power supply, while in some remote places where there is no public power grid, the power generation device is able to be used for power supply, which is not restricted by the operating environment. Preferably, the power generation device is a gas generator set, a diesel generator set or a turbine generator set.

According to the first preferred embodiment of the present invention, the water storage device is a flexible water tank. The clean water in the fracturing operation is stored by the flexible water tank. The flexible water tank has several times the capacity of the conventional water tank while occupying less space than the conventional water tank. Moreover, the flexible water tank is able to greatly reduce the transportation cost by folding transportation.

According to the first preferred embodiment of the present invention, the electric energy provided by the public power grid or the power generation device enters a high-voltage distribution station, the high-voltage distribution station distributes the electric energy into at least one of the fracturing device, the water storage device, the blending device, the sand mixing device, the fluid preparing tank, the sand storage and conveying tank, the low-pressure manifolds and the high-pressure manifolds. The high-voltage distribution station is connected with the public power grid or the power generation device through poles for power supply, the electric energy is distributed to every electric device by the high-voltage distribution station, and the rotational speed of the electrically-driven fracturing pump is controlled by a fracturing frequency conversion station.

According to the first preferred embodiment of the present invention, the electric fracturing operation system further comprises a command and control center, which is powered by the high-voltage distribution station and is configured to control the fracturing device, the water storage device, the blending device, the sand mixing device, the fluid preparing tank, the sand storage and conveying tank, the low-pressure manifolds and the high-pressure manifolds. Therefore, the command and control center is used to control the coordination of various devices, and to monitor the entire hydraulic fracturing system.

According to the first preferred embodiment of the present invention, any one of the fracturing device, the water storage device, the blending device, the sand mixing device, the fluid preparing tank, the sand storage and conveying tank, the low-pressure manifolds and the high-pressure manifolds is electrically driven for achieving full electric drive and no hydraulic drive.

According to the first preferred embodiment of the present invention, the fracturing device and the blending device are vehicle-mounted or skid-mounted, which is able to adapt to different operating environments, and facilitate the transportation and transfer of devices. Specifically, when the operating environment of the road is good, the vehicle-mounted manner is able to be used. When the operating environment is the snow area, the skid-mounted manner is able to be used.

According to the first preferred embodiment of the present invention, every fracturing frequency conversion station is corresponding to one or two electrically-driven fracturing pumps. In practice, every fracturing frequency conversion station is able to control one or two electrically-driven fracturing pumps.

According to the first preferred embodiment of the present invention, every electrically-driven fracturing pump is a three-cylinder or five-cylinder plunger pump. Preferably, a power of every electrically-driven fracturing pump is larger than or equal to 4500 HP. The electrically-driven fracturing pump with high power is able to replace traditional multiple fracturing trucks, which greatly decreases the floor area of well pad during fracturing operations and significantly reduces connecting pipelines between fracturing devices.

According to the first preferred embodiment of the present invention, there are multiple water storage devices which are connected with each other in series and then connected with the blending device. According to the water quantity, the number of water storage devices is able to be increased or decreased to jointly realize the storage of fracturing water, which is more flexible and convenient to use.

According to the first preferred embodiment of the present invention, there are multiple fluid preparing tanks which are connected with each other in series and then connected with the sand mixing device. The number of fluid preparing tanks is able to be increased or decreased according to the amount of the fracturing base fluid after mixing, which is more flexible and convenient to use.

According to the first preferred embodiment of the present invention, the fluid preparing tank, the water storage device, the sand mixing device and the sand storage and conveying tank are arranged in a fracturing fluid preparation area. The fracturing fluid is prepared in the fracturing fluid preparation area. The fracturing fluid preparation area is a low-pressure area, a high-pressure area is located outside the low-pressure area, which optimizes the layout of the electric fracturing operation system, thus improving the operational safety.

Second Embodiment

As shown in FIG. 2 , an electric fracturing operation system according to a second embodiment of the present invention is illustrated. On the basis of the first embodiment, the electric fracturing operation system according to the second embodiment of the present invention further comprises an acid storage tank and an acid supply device, wherein the acid storage tank provides acid for the fracturing device through the acid supply device, and the acid supply device is powered by the high-voltage distribution station and controlled by the command and control center.

The foregoing are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modification, equivalent substitution and improvement made within the principles of the present invention shall be included within the protection scope of the present invention. 

1. An electric fracturing operation system, comprising a fracturing device, a water storage device, a blending device, a sand mixing device, a fluid preparing tank and a sand storage and conveying tank, wherein: the fracturing device comprises multiple electrically-driven fracturing pumps and fracturing frequency conversion stations; the water storage device is connected with the blending device; the blending device is configured to blend fracturing base fluid and store the fracturing base fluid in the fluid preparing tank; the fluid preparing tank is connected with an inlet of the sand mixing device or inlets of the fracturing device; the sand storage and conveying tank is connected with the inlet of the sand mixing device; an outlet of the sand mixing device is connected with the inlets of the fracturing device through low-pressure manifolds; and a wellhead is connected with outlets of the fracturing device through high-pressure manifolds.
 2. The electric fracturing operation system according to claim 1, wherein a power source of the electric fracturing operation system is a public power grid or a power generation device.
 3. The electric fracturing operation system according to claim 1, wherein the water storage device is a flexible water tank.
 4. The electric fracturing operation system according to claim 2, wherein electric energy provided by the public power grid or the power generation device enters a high-voltage distribution station, the high-voltage distribution station distributes the electric energy into at least one of the fracturing device, the water storage device, the blending device, the sand mixing device, the fluid preparing tank, the sand storage and conveying tank, the low-pressure manifolds and the high-pressure manifolds.
 5. The electric fracturing operation system according to claim 4, further comprising a command and control center, which is powered by the high-voltage distribution station and is configured to control the fracturing device, the water storage device, the blending device, the sand mixing device, the fluid preparing tank, the sand storage and conveying tank, the low-pressure manifolds and the high-pressure manifolds.
 6. The electric fracturing operation system according to claim 5, wherein any one of the fracturing device, the water storage device, the blending device, the sand mixing device, the fluid preparing tank, the sand storage and conveying tank, the low-pressure manifolds and the high-pressure manifolds is electrically driven.
 7. The electric fracturing operation system according to claim 6, wherein the fracturing device and the blending device are vehicle-mounted or skid-mounted.
 8. The electric fracturing operation system according to claim 6, wherein each of the fracturing frequency conversion stations is corresponding to one or two electrically-driven fracturing pumps.
 9. The electric fracturing operation system according to claim 6, wherein each of the electrically-driven fracturing pumps is a three-cylinder or five-cylinder plunger pump.
 10. The electric fracturing operation system according to claim 6, wherein the power generation device is a gas generator set, a diesel generator set or a turbine generator set.
 11. The electric fracturing operation system according to claim 1, wherein there are multiple water storage devices which are connected with each other in series and then connected with the blending device.
 12. The electric fracturing operation system according to claim 5, wherein there are multiple fluid preparing tanks which are connected with each other in series and then connected with the sand mixing device.
 13. The electric fracturing operation system according to claim 5, further comprising an acid storage tank and an acid supply device, wherein the acid storage tank provides acid for the fracturing device through the acid supply device, and the acid supply device is powered by the high-voltage distribution station and controlled by the command and control center. 